Fully aromatic polyamides are known to possess properties such as superior tear strength, bulk modulus, thermal resistance, moisture resistance, and chemical stability, which make them one of the most versatile and highly desirable classes of polymers for membrane filtration. It is, however, difficult to prepare membrane casting dopes from such polymers, since they are essentially insoluble in most common organic solvents and only moderately soluble in certain amide solvents (e.g., dimethylformamide and dimethylacetamide), when employed in conjunction with inorganic solubilizing agents. Nevertheless, integrally skinned, hyperfiltration membranes have been produced from aromatic polyamides, as shown in Richter et al., U.S. Pat. No. 3,567,632. Although the desirability of producing porous membranes composed of aramid resins was recognized, the production of such membranes had generally been limited to what the art refers to as "hyperfiltration" membranes, i.e., those which are essentially nonporous and/or have molecular weight cut-offs of less than 300. Recently, however, processes have been disclosed for the production of more open membranes from aromatic polyamides. Japanese Laid-Open Application No. 57-159509 discloses a process for producing membranes with enhanced permeability (i.e., what appears to be ultrafiltration-type membranes) by the addition of an organic swelling agent to a "conventional" polyamide solution, in which the polyamide resin has been solubilized in an aprotic, amide solvent and an inorganic solubilizing agent. U.S. Pat. No. 4,567,009 discloses a process for producing truly porous microfiltration membranes. The process disclosed therein is, however, limited to the casting of such membranes by what is termed the "dry" process of phase-inversion casting. In phase-inversion casting, the casting dope is spread in a film over a smooth surface and the solvent is initially evaporated from the film. In the "wet" process, the film or nascent membrane is then passed through a quenching solution, e.g., water, to extract the water miscible components from the membrane. In the "dry" process, both the solvent and non-solvent components of the film are essentially removed by evaporation in a humidity-controlled atmosphere. The advantage of the "dry" process, partly because of the slow evaporation, is that it provides a good degree of control of pore size--thereby permitting the casting of a membrane with a high degree of openness. The disadvantages are that it is not generally suitable for: (i) large-scale production because of its dependence on the slow evaporation process--generally conducted at about room temperature; and (ii) the production of asymmetrical membranes which are known to provide, at any given pore size, substantially higher flow rates and greater throughput before plugging. It would therefore be desirable to have a means for the "wet" process production of porous membranes composed of aramid resins.